Africa in the Iron Age:
c. 500 B.C. to A.D. 1400

Roland Oliver + Brian M. Fagan

Africa in the Iron Age is a clearly written outline of one of the more
neglected parts of history. It deals with the continent area by area
(with Egypt getting its fair share and no more) and period by period.
The detail is limited by the space available, but the authors (one a
historian and the other an archaeologist) manage to convey a good idea
of the diversity of cultural and political institutions. They also
provide figures and lots of maps — unlike with many works of history,
with this book every time a place name is mentioned and you want a map
it's on the next page!

Note: this book is now rather dated. As a more up to date volume I
recommend Connah's African Civilizations.